Technical Field
The present invention relates to an image forming apparatus configured to control an image forming condition according to a surface property of a recording material.
Description of the Related Art
Conventionally, an image forming apparatus such as a copying machine or a printer, which includes a sensor for determining a type of a recording material, has been provided. Such an image forming apparatus automatically determines a type of a recording material and controls a transfer condition (e.g., a transfer voltage and/or a conveyance speed of a recording material in a transfer period) and a fixing condition (e.g., a fixing temperature and/or a conveyance speed of a recording material in a fixing period) according to the determination result.
An image forming apparatus discussed in Japanese Patent Application Laid-Open No. 2010-283670 emits light to a recording material being conveyed at a constant speed and captures light reflected on the recording material as an image through a complementary metal oxide semiconductor (CMOS) line sensor. Then, the image forming apparatus determines a type of the recording material based on the captured image and controls the image forming condition. With this configuration, a high-quality image can be formed on the recording material.
An image forming apparatus discussed in Japanese Patent Application Laid-Open No. 2013-179532 determines whether there is a breakage or a hole on a recording material by detecting a surface state of the recording material being conveyed therethrough. According to the technique discussed in Japanese Patent Application Laid-Open No. 2013-179532, when a speed of the recording material is accelerated or decelerated, an amount of irradiation light or a reading speed, i.e., a so-called shutter speed, is adjusted according to the speed of the recording material. With this configuration, a surface state of the recording material can be detected with a brightness and/or resolution similar to those of the case where the recording material is conveyed at a constant speed.
However, adjusting the reading speed on a real time basis according to the conveyance speed of the recording material, and finely adjusting the amount of irradiation light as discussed in Japanese Patent Application Laid-Open No. 2013-179532, complicates the operation for detecting the surface state of the recording material. Further, in consideration of the responsiveness of the normally-used light-emitting diode (LED), it can be difficult to make the amount of irradiation light accurately follow the change of the conveyance speed of the recording material.